Document Detail

Long time incubation of monocytic U 937 cells with LDL increases specific paf-acether binding and the cellular acetylhydrolase activity.
MedLine Citation:
PMID:  1804564     Owner:  NLM     Status:  MEDLINE    
Besides the well established role of low density lipoproteins (LDL), the phospholipid PAF-acether (paf) seems to be involved in atherogenesis. The effect of LDL (10 micrograms/ml for 24 h, n = 3) on paf binding characteristics of monocyte/macrophage-like U 937 cells was investigated using the radioligand [3H]paf, unlabeled paf and the paf receptor antagonist WEB 2086. The specific [3H]paf binding significantly increased at 1.4 nM (P less than 0.02) and 2.8 nM (P less than 0.01) added [3H]paf with an increased number of paf binding sites in the Scatchard plot analysis of the data. Specific paf binding was functionally active since paf mediated a cellular [Ca2+]i rise. The protein kinase C (PKC) activator PMA (1 nM, 37 degrees C) expressed specific [3H]paf binding already after a 15-min incubation period, indicating a PKC activation as the decisive step of paf receptor expression. LDL also stimulated the paf degrading cellular acetylhydrolase significantly by increasing both Km (9.4 +/- 1.9 vs. 2.0 +/- 0.5 microM, P less than 0.02) and vmax (0.5 +/- 0.2 vs. 0.2 +/- 0.0 nmol/min per mg cell protein, P less than 0.02). The data demonstrate that LDL increases the number of paf receptors on monocyte/macrophage-like U 937 cells and interferes with the dynamics and/or synthesis of the cellular acetyl hydrolase. These effects could be of importance in the pathogenesis of atherosclerosis.
R Korth; M Middeke
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Chemistry and physics of lipids     Volume:  59     ISSN:  0009-3084     ISO Abbreviation:  Chem. Phys. Lipids     Publication Date:  1991 Oct 
Date Detail:
Created Date:  1992-05-06     Completed Date:  1992-05-06     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0067206     Medline TA:  Chem Phys Lipids     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  207-13     Citation Subset:  IM    
Inst. für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, Munich, F.R.G.
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MeSH Terms
Acetylesterase / drug effects,  metabolism*
Azepines / pharmacology*
Cell Line / drug effects,  metabolism
Lipoproteins, LDL / metabolism*
Macrophages / drug effects,  metabolism
Monocytes / drug effects*,  metabolism
Platelet Activating Factor / antagonists & inhibitors,  drug effects,  metabolism*
Tetradecanoylphorbol Acetate / metabolism
Triazoles / pharmacology*
Reg. No./Substance:
0/Azepines; 0/Lipoproteins, LDL; 0/Platelet Activating Factor; 0/Triazoles; 105219-56-5/WEB 2086; 16561-29-8/Tetradecanoylphorbol Acetate; EC

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